Support pin methods in which a board is supported by bringing plural support pins into contact with a lower surface are employed widely as board support methods for supporting a board from a lower side in component mounting processes of mounting electronic components on a board. In such support pin methods, in the case where there are already mounted components that have already been mounted on the lower side of a board in a preceding process, it is necessary to determine an arrangement of support pins by selecting locations that enable supporting (supportable positions) without causing positional interference with the already mounted components. The determination of an arrangement of support pins is done in such a manner that an operator observes the arrangement of electronic components on an already mounted surface at a manufacturing site and thereby finds supportable locations. Various kinds of assisting apparatus have come to be employed to facilitate this pin arrangement work (refer to Patent Document 1, for example). In the related art technique disclosed in this Patent Document, an image of an already mounted surface and an image indicating the arrangement of pin holes where support pins are disposed are displayed in superimposition to enable a visual check as to occurrence/non-occurrence of interference between the support pins and the already mounted components.